linux/rust/macros
Benno Lossin 22eed6068d rust: macros: allow generic parameter default values in #[pin_data]
Add support for generic parameters defaults in `#[pin_data]` by using
the newly introduced `decl_generics` instead of the `impl_generics`.

Before this would not compile:

    #[pin_data]
    struct Foo<const N: usize = 0> {
        // ...
    }

because it would be expanded to this:

    struct Foo<const N: usize = 0> {
        // ...
    }

    const _: () = {
        struct __ThePinData<const N: usize = 0> {
            __phantom: ::core::marker::PhantomData<fn(Foo<N>) -> Foo<N>>,
        }
        impl<const N: usize = 0> ::core::clone::Clone for __ThePinData<N> {
            fn clone(&self) -> Self {
                *self
            }
        }

        // [...] rest of expansion omitted
    };

The problem is with the `impl<const N: usize = 0>`, since that is
invalid Rust syntax. It should not mention the default value at all,
since default values only make sense on type definitions.

The new `impl_generics` do not contain the default values, thus
generating correct Rust code.

This is used by the next commit that puts `#[pin_data]` on
`kernel::workqueue::Work`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240309155243.482334-2-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-07 22:03:42 +02:00
..
concat_idents.rs rust: macros: add concat_idents! proc macro 2022-12-04 01:59:04 +01:00
helpers.rs rust: macros: allow generic parameter default values in #[pin_data] 2024-04-07 22:03:42 +02:00
lib.rs rust: support srctree-relative links 2023-12-21 20:54:17 +01:00
module.rs rust: module: place generated init_module() function in .init.text 2024-02-25 19:17:31 +01:00
paste.rs rust: macros: update 'paste!' macro to accept string literals 2023-12-14 20:14:01 +01:00
pin_data.rs rust: macros: allow generic parameter default values in #[pin_data] 2024-04-07 22:03:42 +02:00
pinned_drop.rs rust: init: add PinnedDrop trait and macros 2023-04-12 18:41:05 +02:00
quote.rs rust: add derive macro for Zeroable 2023-08-21 14:31:48 +02:00
vtable.rs rust: macros: vtable: fix HAS_* redefinition (gen_const_name) 2023-08-09 21:15:07 +02:00
zeroable.rs rust: macros: add decl_generics to parse_generics() 2024-04-07 22:03:42 +02:00